This application is a 35 USC 371 of PCT/EP99/00071 filed Jan. 8, 1999.
The present invention relates to a spring coiling machine and also a method for switching a spring coiling machine between at least two wires during operation. Various types of such spring coiling machine are already known. They are used for making essentially helical springs from wire.
A drawback with all known types of machine is that adapting to different wire diameters is always laborious and costly. Essential components of known spring coiling machines are designed for the diameter of the wire to be worked with, and must be replaced in order to work with wires of other diameters. This particularly applies to the drive and wire guide. It means that the machine has to be set up all over again. The entire operation takes several hours. A quick changeover of the machine, so as to be able to respond flexibly, is not possible. Also, the components which need to be replaced must be properly stored to protect them from damage and dirt. Providing storage is expensive.
Therefore the problem of the present invention is to develop a spring coiling machine of the kind stated in the introduction so that it is possible to switch to other wire diameters in a very short time; and also to provide a method of doing so.
In accordance with the invention this problem is solved by the technical teaching of the independent claims.
The spring coiling machine according to the invention has a drive that is capable of optionally driving one or other of at least two wires that are sitting in the wire guide at the same time. Both the drive and the wire guide are able to receive and handle a series of wires at the same time although only one wire at a time is actually being fed.
The need for complicated replacement of components and resetting of the machine completely disappears. The switch between at least two wires is made quickly.
The wire guide preferably comprises a guide block in which bores, or opposing grooves that are open on one side, are formed to receive the wires; these bores or grooves lead into a common chamber with an outlet opening. The point of delivery from the wire guide to the cutter and coiler remains constant, and must not be varied.
To permit adaptation to wires of markedly differing diameters, an additional adapter may be provided. This has bores of different sizes. Each of these bores has a larger diameter on the side facing towards the guide block and a reduced diameter on the side facing away from the guide block. They are preferably composed of two sections, one approximately in the form of a truncated cone and the other one approximately cylindrical. The adapter is rotatable or slidable with respect to the guide block to allow the various bores to be combined with the latter.
A common drive may be provided for all wires. This preferably consists of pairs of opposing rollers provided with a number of grooves. The number of grooves corresponds to the number of wires that may be handled. The rollers are displaceable in relation to one another in a direction parallel with their rotational axis. The distances between the grooves on the rollers [of a given pair] are different. The spaces to accommodate the wires to be conveyed, formed by the groove-openings in the opposing rollers, are adaptable to the circumference of the wire. Feeding of more than two wires, e.g. of three or four wires, is also possible. When four wires are fed, each pair of rollers delivers two wires.
The wires sit in grooves on one roller. The grooves on the rollers are arranged so that in any given position of the rollers only one groove of the first roller is in register with a groove of the second roller. Therefore only one wire is driven at any one time. When the rollers are shifted in relation to one another, other grooves are brought into register with each other; the driven wire is then the wire sitting in the pair of grooves concerned.
The radial clearance and axial distance between the rollers are preferably adjustable.
In another embodiment, the rollers do not form alignable groove-spaces to be opened and closed as required. A single wire sits in each roller pair, and is fed as required. All roller pairs are aligned with a central meeting point. Individual wires are fed as required by controlling the drive to each roller pair. Under CNC, only one roller pair is driven at any one time to feed the wire held between the rollers to the central meeting point.
With regard to the first of the embodiments mentioned, the method according to the invention provides for the second or subsequent wires to be held ready inside the guide tube as the first wire is being worked with. A description of the embodiment will now be given in relation to two wires for the sake of simplicity, as follows:
Both wires are accommodated in a guide block with a common outlet opening. After the first wire has been worked with for the desired amount of time, [it] is cut, and is retracted sufficiently to allow the second wire to be fed through the common outlet.
Preferably, only one wire is driven at a time, the drive being switched accordingly. While the wire is being retracted, other components of the machine, in particular the cutter and coiler mechanisms, can be adapted to the incoming wire. This adaptation is preferably made automatically.
Besides the guide block; the wire guide may have an adapter so that the size of the delivery opening of the wire guide can be varied to allow wires of an extremely wide range of sizes to be handled without modifications to the machine.
The subject-matter of the present invention follows not only from the subject-matter of the individual claims [considered separately], but also from the individual claims taken in combination with each other.
All details and features disclosed in the documents, including the abstract, and in particular the configurative form shown in the drawings, are claimed as essential to the invention insofar as, taken separately or in combination, they are novel in relation to the state of the art.